Napsin A is a pepsin-like aspartic proteinase. It is expressed in type II pneumocytes and in adenocarcinomas of the lung and kidney. Studies have shown that Napsin A is both a more sensitive and specific marker than TTF-1 and is extremely specific for lung adenocarcinomas. Most studies show Napsin A is 100% specific for lung adenocarcinoma versus lung SqCC.
When used in combination, Desmoglein 3 + Napsin A are very sensitive and specific markers for discriminating between lung squamous cell carcinoma and lung adenocarcinoma. Used as a panel with TTF-1 and CK5, this antibody combination is extremely accurate and may be used as a first-line screener for lung cancer.
Human Napsin A
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